Summary

To combine input datasets into a new output dataset, use the Merge tool.

Illustration

Usage

Use this tool to add new features or other data from multiple datasets into an existing dataset. This tool can append point, line, or polygon feature classes, tables, rasters, annotation feature classes, or dimensions feature classes into an existing dataset of the same type. For example, several tables can be appended to an existing table, or several rasters can be appended to an existing raster dataset, but a line feature class cannot be appended to a point feature class.

The Field Map parameter in the Append tool can be used to control how the attribute information from the input dataset fields is transferred to the target dataset. The Field Map parameter can only be used if Use the Field Map to reconcile schema differences is chosen for Schema Type.

This tool will not planarize features when they are added to the target dataset. All features from both the input feature class and the target feature class will remain intact after the append, even if the features overlap. To combine, or planarize, feature geometries, use the Union tool.

If Input schema must match target schema is chosen for Schema Type (schema_type = "TEST" in Python) , the schema (field definitions) of the input datasets must match that of the target dataset for the features to be appended. If Use the Field Map to reconcile schema differences is chosen (schema_type = "NO_TEST" in Python), the input dataset schema (field definitions) do not have to match the target dataset. However, any fields from the input datasets that do not match the fields of the target dataset will not be mapped to the target dataset unless the mapping is explicitly set in the Field Map parameter.

Because the input datasets' data is written to an existing target dataset that has a predefined schema (field definitions), the Field Map parameter does not allow for fields to be added or removed from the target dataset.

If the spatial references of an input and target feature class do not match, the Append tool will project the features in the input feature class to the coordinate system used by the target feature class.

This tool does not perform edge matching; there will be no adjustment to the geometry of features.

Map layers can be used as Input Datasets. If a layer has a selection, only the selected records (features or table rows) are used by the Append tool.

This tool cannot use multiple input layers with the same name. To work around this limitation, use the tool dialog box browse button to browse for the full paths of each of the Input Datasets.

To use the Subtype parameter, the target dataset must have a defined subtype field and assigned subtype codes. In the Subtype parameter, provide a subtype description to assign that subtype to all new data that is appended to the target dataset.

Syntax

The input datasets containing the data to be appended to the target dataset. Input datasets can be point, line, or polygon feature classes, tables, rasters, annotation feature classes, or dimensions feature classes. Each input dataset must match the data type of the target dataset.

Table View; Raster Layer

target

The existing dataset where the input datasets' data will be appended.

Table View; Raster Layer

schema_type

(Optional)

Specifies whether the schema (field definitions) of the input datasets must match the schema of the target dataset for data to be appended.

TEST —Input dataset schema (field definitions) must match the schema of the target dataset. An error will be returned if the schemas do not match.

NO_TEST —Input dataset schema (field definitions) do not have to match the schema of the target dataset. Any fields from the input datasets that do not match the fields of the target dataset will not be mapped to the target dataset unless the mapping is explicitly set in the Field Map parameter.

String

field_mapping

(Optional)

Controls how the attribute fields from the input datasets are transferred or mapped to the target dataset. This parameter can only be used if the schema_type parameter is NO_TEST.

Because the input datasets' data is appended to an existing target dataset that has a predefined schema (field names and types), fields cannot be added or removed from the target dataset. You can set merge rules for each output field.

Merge rules allow you to specify how values from two or more
input fields are merged or combined into a single output value.
There are several merge rules that determine how the output field is populated with values.

Append example 2 (stand-alone script)

The following script demonstrates how to use the Append tool.

# Name: Append.py# Description: Use the Append tool to combine several shapefiles# import system modules importarcpyimportos# Set environment settingsarcpy.env.workspace="C:/data"# Set local variablesoutLocation="C:/Output"outName="MA_towns.shp"schemaType="NO_TEST"fieldMappings=""subtype=""# Process: Create a new empty feature class to append shapefiles intoemptyFC=arcpy.CreateFeatureclass_management(outLocation,outName,"POLYGON","amherst.shp")# All polygon FCs in the workspace are MA town shapefiles, we want to append # these to the empty FC. The list will resemble ["amherst.shp", "hadley.shp", # "pelham.shp", "coldspring.shp"] fcList=arcpy.ListFeatureClasses("","POLYGON")# Create FieldMappings object to manage merge output fieldsfieldMappings=arcpy.FieldMappings()# Add the target table to the field mappings class to set the schemafieldMappings.addTable(emptyFC)# Add input fields for the town name into TOWNNAME field that matches the # target dataset since each input dataset has a different field name for # this infofldMap=arcpy.FieldMap()fldMap.addInputField("amherst.shp","TOWNNAME")fldMap.addInputField("hadley.shp","NAME")fldMap.addInputField("pelham.shp","TOWN_NAME")fldMap.addInputField("coldspring.shp","TOWN")# Set name of new output field "TOWNNAME"townName=fldMap.outputFieldtownName.name,townName.aliasName,townName.type="TOWNNAME","TOWNNAME","TEXT"fldMap.outputField=townName# Add output field to field mappings objectfieldMappings.addFieldMap(fldMap)# Do the same thing for the POPULATION fieldfldMap=arcpy.FieldMap()fldMap.addInputField("amherst.shp","POPULATION")fldMap.addInputField("hadley.shp","POP")fldMap.addInputField("pelham.shp","POP_2010")fldMap.addInputField("coldspring.shp","POP")# Set name of new output field "POPULATION"pop=fldMap.outputFieldpop.name,pop.aliasName,pop.type="POPULATION","POPULATION","LONG"fldMap.outputField=pop# Add output field to field mappings objectfieldMappings.addFieldMap(fldMap)# Process: Append the feature classes into the empty feature classarcpy.Append_management(fcList,os.path.join(outLocation,emptyFC),schemaType,fieldMappings,subtype)